Faceglued Blockboard from Low-Grade Northern Hardwoods

Blockboard is a form of lumber core plywood, the latter a product that has for years been used in the United States and Canada in furniture and cabinet manufacture. A unique manufacturing process and the fact that glulines in faceglued blockboard are found only between face veneers and core serve to distinguish this product from the typical lumber core panel. Blockboard panels have become increasingly popular in northern Europe in recent years, where they have found application in products such as industrial shelving, storage units, packing cases, doors and partitions, benching, work-tops, and even combination subflooring/underlayment.This report deals with a technical and economic evaluation of prospects for manufacture of blockboard panels from low-grade hardwoods of the United States. Faceglued blockboard was manufactured in various configurations from aspen (core) and elm (faces) and then evaluated as a general purpose structural panel. Test data indicate that blockboard panels made with a low-density hardwood core of short-length pieces would have strength and dimensional properties very similar to softwood plywood if manufactured to slightly greater thickness. Economic projections show that these thicker panels could be delivered to midwestern markets at a price very close to that of softwood plywood panels of comparable strength

Faceglued Blockboard—An Alternative to Plywood?

Faceglued blockboard, a European product similar to lumber core plywood (but with no edge gluing of core strips), was evaluated from both technical and economic perspectives as a general purpose structural panel. Blockboard was found to have strength and dimensional properties comparable to other wood-based structural sheet materials, though performance after accelerated aging suggests limits to exterior applications. Economic projections indicate little difference in costs of production between softwood plywood and blockboard

Environmental Implications of Wood Production in Intensively Managed Plantations

Although many of the issues raised about forest plantations are non-trivial, there are a number of significant environmental advantages of plantation establishment that appear to outweigh concerns, if plantation management practices can be developed to address concerns regarding sustainability. Foremost among the advantages is that establishment of highly productive forest plantations can provide large quantities of wood and fiber from relatively small land areas, raising the possibility that pressures for harvesting within natural forests can be markedly reduced. Moreover, assuming that forest plantations are carefully established and managed, they have the potential to produce a continuous, renewable stream of industrial raw materials that results in less overall environmental impact than other types of raw materials. Assessment of total environmental impacts over product life cycles shows that structural and nonstructural wood and wood fiber products made from plantation-derived raw material yield markedly lower impacts than similar products made from metallic, cementitious, petroleumbased, or other raw materials. Similarly, examination of total environmental impacts of papermaking fiber production in forest plantations versus fiber production using annual agricultural crops shows significant advantages to wood fiber. Thus, forest plantations can yield environmental benefits that extend well beyond the geographic location in which they are located

Simulation Modeling of Particleboard Density Profile

Particleboard properties are affected by the vertical density profile among other factors. To predict or model board properties, one needs to determine the density profile. A simulation model was developed in this study to model the vertical density profile by simulating the hot pressing process of a particleboard. Temperature and moisture content profiles during hot pressing in the thickness direction of a pressed mat and the influential factors affecting wood compressibility were modeled such that they can be determined at any moment of pressing. The models developed allow calculations of the profiles to be carried out by either the finite difference method or an alternative approximation method presented herein. The density profile was modeled based on the compressibility and the resulting strain of each layer of the board thickness due to pressing

Modeling of Strength Properties of Structural Particleboard

The strength properties of structural particleboard are critically important factors. In designing a particular particleboard, a series of experiments can be run to determine the effect of a particular combination of factors. Modeling could be used as an alternative approach. Simulation modeling is one of the modeling techniques that can be fast and cost-effective. Structural particleboard was modeled in this study as a multilayer system that consists of a number of thin and uniform layers that exhibit different strength properties between layers, but the same properties within each layer. The effective modulus of elasticity of a board is a resultant of the combined effect of the modulus of all the layers. The modulus of rupture was obtained by determining the ultimate force or maximum moment during the simulated bending test. Internal bond strength was modeled using a modified regression equation

The Extratropical Transition of Tropical Cyclones: Forecast Challenges, Current Understanding, and Future Directions

A significant number of tropical cyclones move into the midlatitudes and transform into extratropical cyclones. This process is generally referred to as extratropical transition (ET). During ET a cyclone frequently produces intense rainfall and strong winds and has increased forward motion, so that such systems pose a serious threat to land and maritime activities. Changes in the structure of a system as it evolves from a tropical to an extratropical cyclone during ET necessitate changes in forecast strategies. In this paper a brief climatology of ET is given and the challenges associated with forecasting extratropical transition are described in terms of the forecast variables (track, intensity, surface winds, precipitation) and their impacts (flooding, bush fires, ocean response). The problems associated with the numerical prediction of ET are discussed. A comprehensive review of the current understanding of the processes involved in ET is presented. Classifications of extratropical transition are described and potential vorticity thinking is presented as an aid to understanding ET. Further sections discuss the interaction between a tropical cyclone and the midlatitude environment, the role of latent heat release, convection and the underlying surface in ET, the structural changes due to frontogenesis, the mechanisms responsible for precipitation, and the energy budget during ET. Finally, a summary of the future directions for research into ET is given

The Effect of Core Block Length on Strength of Faceglued Blockboard

Blockboard is a form of lumber core plywood, the latter a product that has for years been used in the United States and Canada in furniture and cabinet manufacture. A unique manufacturing process and the fact that gluelines in faceglued blockboard are found only between face veneers and core serve to distinguish this product from the typical lumber core panel. Blockboard panels have become increasingly popular in northern Europe in recent years, where they have found application in products such as industrial shelving, storage units, packing cases, doors and partitions, benching, worktops, and even combination subflooring/underlayment.Earlier work has indicated that blockboard of comparable strength to plywood could be manufactured from northern hardwoods and delivered to Upper Midwestern markets at a price very close to that of structural plywood. This work identified cost of raw materials for the panel core as a key element in lowering cost of production of blockboard. This report deals with the technical feasibility of using short length core blocks (which should maximize yield from low-grade and scrap wood) in the manufacture of three-ply faceglued blockboard.Test data indicate that it would be possible to make structural faceglued blockboard panels using short core blocks. It was concluded that if blockboard panels were manufactured to a slightly greater thickness than plywood with which it might compete, comparable strength to plywood could be obtained using core blocks as short as 8 inches (20.3 cm)

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xviii, 719 p.; 21 cm